On the practical applicability of SDN research

Software-Defined Networking (SDN) is a de-facto established approach that separates the packet switching functions of a device from its operational logic, which is controlled by a piece of software. Due to its potential for realizing new network architectures and services, a whole thread of scientific literature is devoted to SDN and its most adopted incarnation, OpenFlow. However, limited attention has been put in verifying the viability of the proposed approaches on currently available hardware. We address this deficiency through the following contributions: i) a critical review of the literature about SDN in terms of applicability issues stemming from publicly documented limitations of OpenFlow implementations; ii) a methodology for verifying the support of SDN-related functions in a network device, comprising an OpenFlow compliance test as well as custom targeted tests; iii) an application of the methodology to devices from 7 different vendors, unveiling extensive anomalous behaviors affecting even the most basic features; iv) a discussion of this outcome in terms of relevance of the discovered anomalies and of their implications on the applicability of state-of-the-art contributions on SDN. Besides taking a snapshot of the viability of research results, with this paper we intend to highlight aspects that operators should consider when picking SDN devices.